Page 272 -

B

Green IT and Cloud

Computing

“Cloud computing is reshaping the IT marketplace,
creating new opportunities for suppliers, and catalyz-
ing changes in traditional IT offerings.”

—IDC, October 20, 2008

ptg
Cloud computing has been receiving a great deal of attention in IT
during the past year. It is, in actuality, a new label (as of late 2007) for
the subset of grid computing that includes utility computing and other
approaches to the use of shared computing resources. Cloud computing
is an alternative to having local servers or personal devices handling
users’ applications. Essentially, it is an idea that the technological capa-
bilities should hover over everything and be available whenever a user
wants. Cloud and grid computing were introduced in Chapter 6, “A
Most-Significant Step—‘Virtualizing’ Your IT Systems.” This appendix
expands on the subject and was mostly written by Ravi Subramaniam,
IBM Software IT Architect.
The concept of grid computing has been around for a decade. It’s
defined by the Global Grid Forum (www.gridforum.org) as “distributed
computing over a network of heterogeneous resources across domain
boundaries and enabled by open standards.” The IT industry has used
server cluster technology and distributed computing over networks for
many years; however, grid and cloud computing are major steps forward
because of their use of open source middleware to virtualize resources
across domains.

237